One more thing, 

I spent the extra money on the nice back band/seat combination for my 16; but my wife and buddy (who mainly use the boat) can't get the back comfortable. 

A buddy bought a kayak with a *SUPER* nice seat; where the back is linked to the bottom. I've looked online but not been able to find something like that for me to pick up. Does anyone have any suggestions? 

I'm a plans builder looking at scarf vs. puzzle joint for my Passagemaker.  First of all, scarf joints are extinct, CLC does puzzle joints because they can and they're economically feasible. 

It's very easy for a plans builder to do a scarf joint with a 1:8 slope on your panels.  The jig is very easy to setup

With that being said, with the same router you'd use for the scarf joint, you can also make your own puzzle joint.  I recently looked at a dovetail router template at Rockler that had fingers that were exactly the same size as the gaps in the spacing, leading me to believe that i would make a perfectly good, but non-locking puzzle joint (see pic above from Christine DeMerchant's build).  I've also seen guys who have designed their puzzle joint in a CAD program, printed it out and cut close to the line and then cleaned it up with a spindle sander.

Basically, there are many different ways to skin this cat.  I prefer the look of a scarf joint and as an old school sailor/woodworking purist I'll probably go that route, but I just wanted to have options.

Of course the biggest benefit of the puzzle joint is that it locks the parts in the proper orientation so you can't and more or less "rocker" to the plank than the design intended.  With scarf joints, the glue-up can go horribly wrong.  I believe I saw a video of John addressing this by laying out reference lines and nails to act as stops to keep the panels in the proper orientation.  It's just a matter of being careful and getting everything setup properly before you mix up some epoxy.

CLC says that the boat is good for paddlers up to 270#.  He's been right before I take it  as truth.  Of course everybody's extra 80# are in different places.

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If you took the 16 camping the 18 will have more room.  Look at the knee height and shoe size in the specifications.

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If you made two scarf joints in the 16 you should be able to make  2, 4, 6, etc.  Be nervous but don't be scared.   First off YOU are building the boat. If you want to scarf the joint, butt the joint, puzzle joint  or finger  the joint, go ahead .  They stopped scarf joints mostly for shipping and cutting concerns.

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A hand done puzzle joint is possible. Make a pattern. Score the wood with exacto knife. Cut the wood proud. Sand to fit. Piece of cake.............er wood. :-) You just have to be a little exacting, or perhaps OCD. The scarf joint is easier.   

So do the plans recommend puzzle joints? Do they give you directions for how to pull that off? I mean, I read the New Kayak Shop and the guide and it gave pretty good scarf joint directions. 

Honestly, I've done scarf joints so I feel more comfortable with them. I don't have a router.  Maybe I just had beginners luck but they turned out okay. I just used a hand planer and some care. 

It sounds like your saying I have that option still. 

Thanks Both of you. I will stick with what I know. :-). 

I love doing this, but my wood working skills are limited. The 16 took me 2 years to build because it was alot of 'Read. Read. Cut, Read, get more wood, read, cut, move to next step'. :-) But the directions are awesome. 

have either of you paddled an '18? 

  Puzzle joints are just if you buy the kit. Working from plans you still do scarf joints. I'm building the Shearwater Sport from plans and found the scarfs easy enough with a sharp low angle block plane.

   Have you thought about a Wood Duck 14?

I'm not sure if it needs mentioning, but there is an interesting "cheat" built in when doing scarf joints by hand with a plane.  The layers of plywood give you "topo" lines to work with.  If all the layers of your 1/4" plywood are nice, straight, parallel across 2" (1/4x8), then you're golden!

   I have looked at the Wood Duck. I'm still partial to the Chesapeake. :-). But thank you. 

I used the 'topo lines' method before. I don't mind scarf joints, I'm just glad to know they are still used. I was really worried if I had to cut puzzle joints.